If "docker compose images" logs to stderr, task execution fails

[niels-hb]

SUMMARY

ISSUE TYPE

• Bug Report

COMPONENT NAME

community.docker.docker_compose_v2

ANSIBLE VERSION

ansible [core 2.19.4]
  config file = ./ansible/ansible.cfg
  configured module search path = ['~/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /nix/store/90jiynl0ah5z92p41xg4n2vbkdqayfci-python3.13-ansible-core-2.19.4/lib/python3.13/site-packages/ansible
  ansible collection location = ~/.ansible/collections:/usr/share/ansible/collections
  executable location = /nix/store/90jiynl0ah5z92p41xg4n2vbkdqayfci-python3.13-ansible-core-2.19.4/bin/ansible
  python version = 3.13.9 (main, Oct 14 2025, 13:52:31) [Clang 21.1.2 ] (/nix/store/hv7qldswrqvg1sjys1lmgjg875hkffng-python3-3.13.9/bin/python3.13)
  jinja version = 3.1.6
  pyyaml version = 6.0.3 (with libyaml v0.2.5)

COLLECTION VERSION

Collection       Version
---------------- -------
community.docker 5.0.3

CONFIGURATION

CONFIG_FILE() = ./ansible/ansible.cfg
DEFAULT_HOST_LIST(./ansible/ansible.cfg) = ['./ansible/inventory.yaml']
DEFAULT_ROLES_PATH(./ansible/ansible.cfg) = ['./ansible/roles']
EDITOR(env: EDITOR) = nvim

GALAXY_SERVERS:

OS / ENVIRONMENT

Remote host: Rocky Linux 10.0 (Red Quartz) - x86_64
Ansible host: macOS 26.1 - Apple M3

STEPS TO REPRODUCE

- name: Run docker-compose.yaml
  community.docker.docker_compose_v2:
    project_src: /opt/vault_agent
    state: "present"

services:
  vault-agent:
    image: hashicorp/vault:1.21
    restart: always

EXPECTED RESULTS

call_cli_json should not fail if stdout doesn't contain data.

ACTUAL RESULTS

TASK [vault_agent : Run docker-compose.yaml] ***********************************
[ERROR]: Task failed: Module failed: Error while parsing JSON output of /usr/bin/docker --host unix:///var/run/docker.sock compose --ansi never --progress json --project-directory /opt/vault_agent images --format json: Expecting value: line 1 column 1 (char 0)

fatal: [1.2.3.4]: FAILED! => {"changed": false, "msg": "Error while parsing JSON output of /usr/bin/docker --host unix:///var/run/docker.sock compose --ansi never --progress json --project-directory /opt/vault_agent images --format json: Expecting value: line 1 column 1 (char 0)\nJSON output: "}

Command used to debug behavior:

/usr/bin/docker --host unix:///var/run/docker.sock compose --ansi never --progress json --project-directory /opt/vault_agent images --format json > /tmp/stdout 2> /tmp/stderr

/tmp/stdout (empty file):

/tmp/stderr:

{"error":true,"message":"Error response from daemon: image with reference hashicorp/vault:1.21 was found but does not provide the specified platform (linux/amd64)"}

Possibly relevant code:

• https://github.com/ansible-collections/community.docker/blob/5.0.3/plugins/module_utils/_common_cli.py#L197
• https://github.com/ansible-collections/community.docker/blob/5.0.3/plugins/module_utils/_compose_v2.py#L937
• https://github.com/ansible-collections/community.docker/blob/5.0.3/plugins/modules/docker_compose_v2.py#L514

[felixfontein]

I guess there are two things we can do:

1. Don't fail the task if only listing the images fails. Right now it does fail since there is no reason why the listing of images should fail if there isn't something seriously wrong with your system.
2. Also show stderr in the error message, since right now knowing that stdout was empty isn't very helpful.